The present invention relates to buoys which are released from an aircraft on to the surface of the sea, and more particularly to acoustic buoys provided with hydrophones for picking up undersea sounds and retransmitting them by radio to a reception station situated very often in the releasing aircraft.
Such buoys are known more particularly from French Patent No. 2 431 419 and its addition No. 2 464 179 filed in the name of the applicant.
These buoys comprise a device for braking and stabilizing their fall so as to essentially limit the shock effects on impact with the water. This device is formed of a balloon which also serves as float for the buoy after it has reached the water. A hydrophone situated at the lower part of the buoy descends automatically to a given depth when the buoy floats on the water. It picks up the acoustic sounds propagated in the water and transmits them to a radio transmitter contained in the body of the buoy which feeds an antenna supported by the balloon.
The balloon is folded up inside the body of the buoy and is inflated during the fall through a forced air inlet situated at the upper part of the body of the buoy. The lower end of the balloon is crimped to a circular support surrounding the body of the buoy, to which it is held by radial spacers which define a circular space for the forced inlet of air into the balloon. The balloon is further provided with pockets in its upper part, through which the air passes to leave through smaller upper openings, which provides aerodynamic stability of the assembly during the descent through the air.
The system for fixing the float balloon to the body of the buoy by means of a circular support and crimping the balloon to the outside of this support has a certain mechanical fragility. Moreover, the assembly is relatively complex, which leads to fairly high constructional costs.